gbp-import-orig's filter feature was used to remove the bundled 3rdparty/
sources from upstream tarball, for example:

# fetch tags
git remote add up http://git.skylable.com/sx
git remote update up
# import version 1.2
gbp import-orig --upstream-vcs-tag=1.2 -u '1.2+ds' --uscan --verbose
# update debian/changelog version to 1.2+ds-1
....
